The present invention relates to a program processing device, and more particularly, to a control LSI optimal for use when testing the operation of built-in software (firmware).
In recent years, an evaluation chip is normally used when developing software. The evaluation chip includes a CPU of a target system and an interface circuit, which supports software debugging. The evaluation chip, which is mounted on a user board, is connected to an in-circuit emulator (ICE (a registered trademark)). The ICE provides a debug command to the CPU to perform software debugging. Japanese Laid-Open Patent Publication No. 11-282712 describes an example of a debug system that uses an evaluation chip.
In a semiconductor package device, such as a system on a chip (SOC) that lays out a plurality of peripheral circuits including a CPU to realize system level functioning, the bus for the CPU and control signals are concentrated in the chip. This structure decreases the debugging efficiency. More specifically, when developing software for the SOC, CPUs must separately be connected to an evaluation board to undergo debugging. Thereafter, the CPUs and a plurality of peripheral circuits are ultimately integrated in a single chip. This increases the developing cost, prolongs the designing time, and lengthens the turn around time (TAT).
Generally, the number of terminal pins that are used for debugging in an SOC is small to minimize the cost for conducting testing, such as software debugging. Thus, debugging cannot be performed efficiently.
When developing software in a prior art, a breakpoint is set in the source code for a program. The execution of the program is interrupted when reaching the breakpoint to perform debugging. However, the program memory must be rewritten to set the breakpoint. This makes debugging complicated.